FIRST SCIENCE · SECOND CHAPTER · SEVENTH SECTION · Second Article
Second Article
It describes the structure and movements of the eccentric sphere of the planet Venus.
O noble one! It should be known that the scholars of astronomy have said as follows: In order to explain the order and arrangement in the operation of this Venus
star, the second sphere known as the “Carrier” in the body of its deferent sphere is that which extends to the earth.
Its center, at a distance of two degrees from the center of the world by its own diameter and parts, is a spherical body surrounded at the apogee point by two parallel surfaces from the outside.
[48/b] The convex surface of this sphere touches the convex surface of the first sphere at a certain common point, which is called the apogee. And since this is, in relation to the center of the world, the farthest point, when the planet Venus, by the movement of the carrier sphere, comes to this point,
it is found to be very far and high from the center of the earth.
Likewise, the concave surface of the second sphere is also tangent to the concave surface of the first sphere at a common point, which is called the perigee.
The perigee, being the closest point in relation to the center of the world, when the planet Venus, by the movement of the carrier sphere, comes to that point,
it is found to be quite close to the center of the earth and is at its lowest.
In this manner, when the second sphere separates from and empties out of the first sphere, necessarily
two spheres of different thicknesses are formed, one of which
encloses the second sphere, and the other is enclosed together with the second sphere.
The thin side of the enclosing sphere faces the apogee point, while its thick side faces the perigee.
The thin and thick sides of the enclosed sphere are the exact opposite of this.
Since the
entries
of these
two
spheres
in the completion
of the sphere
have been completed, one is called the one that completes the enclosing, and the other is called the one that completes the enclosed.
In essence, each sphere has its own specific movement. As they revolve on their own axes and poles, and as it is inevitable for all of them to complete their rotation, the inclined sphere of the planet Venus,
being beneath the universal sphere of the sun, moves around its own center in the body of its own deferent sphere, with its own unique motion, in accordance with the movement of the luminous sun’s eccentric sphere from west to east,
and at the same time, it also moves the planet Venus along with itself.
In this case, the planet Venus traverses each zodiac sign in twenty-four days. If it lingers in some signs, it remains for four months. It completes its revolution together with the Sun once a year.
The center of Venus’s epicycle never separates from the center of the sun, and since it moves together with its ascending node, the greatest distance of this star from the sun is approximately half the diameter of the epicycle sphere, and at its mean distance, it is about two-thirds of one-sixth of the revolution of the said sphere. That is, when Venus is between the two distant and two mean points of the epicycle sphere, its approximate distance from the sun is forty degrees.